He probably took a look at the story supercut and decided to trash it all.
The delay is because he's refocusing the game to be less linear, and they have to work to patch together a new game out of the old version's scraps.
Except that's really hard
so the planned dlc will instead be the rest of leftovers from the base game, and after that proves to be too difficult to keep up with they'll just toss in exp boosters.
Everything left over from the original cut of MN9 and it's original dlc plans have now been handed to High Moon studios so they can paste it into the fall 2017 sequel.